HIGHTSTOWN, N.J. (KYW Newsradio) — The AP Government class at Hightstown High School in New Jersey is on pins and needles as they wait for President Donald Trump to sign a bill into law. The students spent 3 1/2 years working to get the bill passed.

Social Studies teacher Stuart Wexler is managing anxiety among students.

"We do have a little bit of a time limit on our hands," he said.

The students have just a few hours left to get President Donald Trump's attention and they're hard at work "from tweeting at Kanye West, Kim Kardashian, Sean Hannity," he said.

In 2015, the students decided to help families of racially charged hate crimes from the civil rights era get answers. So they drafted, got support and lobbied to pass the Civil Rights Cold Case Records Collections Act, a bill that creates an independent review board to review, unseal and unredact decades-old case files.

"There are so many crimes that are unsolved," said Oslene Johnson, a graduate of Hightstown High.

She was part of the original class that drafted the bill in 2015.

The next school year, they got Indiana Congressman Bobby Rush to introduce the bill. Then over the years, with the help of media coverage, they gained support. Last year, Senator Doug Jones introduced the bill in the Senate. Both houses passed the bill with overwhelming bipartisan support. Now, all they need is President Trump's signature.

"We just go down the list and call them one at a time," said Cate Yang, a Hightstown senior who has skipped classes (with permission) alongside other students to help call, tweet and email everyone they could think of to ensure the Cold Case Act becomes law.

If the president signs the bill, Wexler says, it'll be a lesson for all.

"If you mobilize and are persistent, you can get things done in this country still," Wexler said.

He says if President Donald Trump fails to sign the Cold Case Act Tuesday, it expires via "pocket veto" and the students will have to start all over.